It's been a long time coming but the functional changeover from Winter to Spring is now at hand.
The six-week dominance of "blocking" high pressure systems over the North Sea and Scandinavia is subsiding. Inbound Atlantic depressions have been deflected around the British isles during this period, but no longer.
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This composite wind speed and direction chart is the forecast for tomorrow (Wed 10.4.2013 at 07:00utc.) The cold dry easterly winds we have known since it seems like forever are about to be replaced by a more familiar south and south-west airstream. Temperatures are set to rise - slowly at first - and there will be more in the way of rain.
This picture will continue changeable for the next two weeks or so, with perhaps a drier and sunnier last week of April, though it's more difficult to look that far ahead.
These southerly winds should help the remaining migrants - especially smaller birds and those that fly at low levels. Those already in the British Isles and struggling northwards toward Scotland will get less help, and the snowfalls there are not over yet.